My hair is growing back thinner after shaving my hair due to severe hair loss, is there anything I can do?

With androgenic alopecia a large percentage of your follicles shift into the resting phase.  Therefore, after you shave, only a small percentage continue growing, while a larger percentage remain dormant and do not grow.  Thus, after you shaved, a smaller percentage of your hair is actually growing and getting longer.  The other hairs are sitting idle on the scalp and not growing.

You should consider products to promote the hair follicles to return to an active growing phase.  These things include sonicated PRP injections and WNT-Act.  Also, consider topical minoxidil.  You can get WNT-act at amazon.com.  This new product up-regulates the WNT pathway or a gene pathway and promotes hair growth.  This is a plant based product imported from Italy and the first product of its kind.  

I can't tell you what is happening because I don't have all your information and I do not have the opportunity to examine the scalp up close myself. These are essential pieces of the puzzle in order to diagnose hair loss. I can tell you one thing though - and that is that the shaving had nothing to do with the hair growing back thinner. Shaving does not affect hair growth patterns as that is a long standing myth. 

Your biggest enemy is the progressive thinning leading to a balding pattern that is not evident at this point in time. The degree of thinning that you are experiencing would suggest that you should seea doctor who most likely will get Bulk Measurements of your hair to determine the degree of the thinning that you are presently having. If the diagnosis is early genetic hair loss (the most common cause of hair loss in young men), then the best treatment would be the drug finasteride which is highly effective in men of your age and may not only stop the hair loss but possibly reverse it. If you are developing a more advanced balding pattern the best test to get will determine the Bulk Measurements of your hair and this will show, over a one-year time frame, how effective the treatment will be. Once you know this information, then you and your doctor need to develop a MASTER PLAN which will define what you need